Java Tutorial - Java Scipt :
HTML
Another markup language similar to XML is the well-known HTML (Hypertext Markup Language). HTML is used to write the majority of Web pages today and also has roots that draw from the ideas in SGML. However, unlike
XML and SGML, HTML is neither extensible nor consistent. Some of the problems with HTML include the following:
· Only a fixed set of tags is defined for use in the document.
· Case sensitivity in tag names is not enforced.
· Tags are not required to be properly closed and nested. For example, the <li> tag does not require a matching </li> tag.
· Attributes within tags are not required to be quoted, which results in greater ambiguity and makes HTML harder to parse.
All in all, this lack of consistency poses problems for the use of HTML as the primary markup language of documents on the Web. HTML tags are generally focused on presentation rather than structure, undermining its usefulness as a data interchange format. Today the push is on to replace HTML with its XML equivalent, XHTML.
